1. Field of the Invention
The present invention relates to the preparation of esters by carbonylating monoolefins, and, more especially, to such carbonylation by reacting carbon monoxide and an alcohol with compounds containing but a single olefinic double bond.
The invention also relates to the preparation of diesters from alkyl pentenoates, and in such respect relates particularly to the synthesis of alkyl adipates by carbonylating alkyl pent-3-enoates.
2. Description of the Prior Art
It is known to this art, from Bulletin of the Chemical Society of Japan, Volume 46, pages 526 and 527 (1973), that a mixture containing dialkyl esters, and in particular an alkyl adipate, is obtained by reacting carbon monoxide and an alcohol with an alkyl pent-3-enoate, under high pressure and at elevated temperature, in the presence of cobalt carbonyl and a heterocyclic and aromatic nitrogen-containing base. However, the industrial-scale development of a technique of this type, the value of which is not contested in principle, is greatly compromised by the low activity of the catalyst system used. Cf. U.S. Pat. Nos. 3,397,226 and 3,668,249.